Feeder



April 20, 1943. H R SCHEMM 2,316,814

FEEDER Filed Marcha, 1940 2 sheets-sheet 1 17 21/\` E i M l jg 20 jg J5 E im Uff? @J J6 Z5 j Z3 Z5 244 O l f 125 @M 71%, a

`ATTQCLJRNEY-S April 20, 1943. H. R. scHl-:MM

FEEDER Filed March 8, 1940 2 Sheets-Sheet 2 INVENTOR. if

Patented Apr. 20, 1943 FEEDER Henry Ripley schenm, Detroit, Mich.

Application March 8', 1940, Serial No. 323,051

Claims.

This invention relates to a feeder for controlling and regulating the flow of powdered material such, for example, as cement, flour, farina and the like.

In the handling of powdered materials such, for example, as cement, it is common practice to store the cement; in large storage bins or silos. Such a silo is provided with a discharge opening in its floor through which the cement is fed by gravity. numerous known expedients being used to facilitate the gravitational flow of the cement. In withdrawing or feeding the cement from the silo it is desirable that the flow be precisely controlled, that is, the rate of flow should be accurately regulated and the flow completely stopped or started instantaneously at the will of the operator. It is one of the objects of this invention to produce a feeder for powdered materials,

such as cement, which will not only accurately regulate the flow of the cement but will also lend itself to precise and instantaneous stopping and starting of such iow.

It is also desirable that the feeder for powdered material should lend itself to ready and easy installation in the known systems for storing and handling such materials and should require but a minimum of space. It is also an object of this invention to produce a feeder for powdered materials which is of simple, compact and inexpensive construction and which readily lends itself to installation in any feed line running from a source of storage of such powdered materials.

In the drawings:

Fig. 1 is a vertical section showing the feeder which is the subject matter of this invention.

l Fig. 2 is an end view taken from the left-hand side of Fig. 1 with the cover plate removed.

Fig. 3 is a. vertical section through a modified form of feeder.

Fig. 4 is a vertical section through a second modified form of the invention.

Referring more particularly to the drawings there is shown a fragmentary portion of a silo i having a floor 2 which is utilized for storage or as a source of a powdered material such as cement.

The floor of the silo is provided with an outlet 3 through which the cement is discharged as indicated by the arrows. To facilitate the discharge of the cement, the cement may be aerated or fluidifled by an arrangement consisting of a floor of porous brick 4 spaced above the floor 2 of the silo on supports 5 to provide a space G. 'I'he space 6 is supplied with compressed air through opening l by line 8 connected with a source of compressed air (not shown). The compressed air passes through the pores of the porous brick 4 and is intimately mixed with the cement so that the cement flows and assumes the characteristic of a fluid. As thus aerated the cement flows by gravity along the upper surface of the porous bricks 4 into outlet 3 and discharge spout 9. The spout 9 extends in an up and down direction so that the ow of cement therethrough is by gravity. After the cement leaves the floor made up by the porous bricks 4 and falls into spout 9, it substantially or pretty much loses its fluid characteristics and again assumes the characteristics of powdered unaerated cement.

For controlling the flow of cement through outlet 3 and spout 9, it is proposed to assemble a feeder, which is the subject of this invention, in spout 9. This feeder in its broad aspects comprises an obstruction to the normal flow by gravity of the powdered material in its unaerated state. The obstruction issuch that the cement in its normal condition cannot flow by the obstruction and therefore the flow of cement through outlet 3 and spout 9 is stopped. The obstruction also assumes such a nature that once the cement is properly aerated, it readily surmounts or passes by the obstruction and establishes free and normal flow of the cement through spout 9. For purposes of description rather than by way of limitation, the feeder will now be described.

In the principal form of the invention the obstruction takes the form of a horizontal offset I0 in spout 9. The offset spout line I0, as shown, is of rectangular cross section but obviously can be of circular or other polygonal cross section.

The oiset l0 is provided vwith a vertically acljustable baiiie Il positioned adjacent the upstream portion Sa of the spout 9. The baflie H may be slidably adjusted upwardly and downwardly in its guide I2 and held in any desired position by the set screw I3. Another vertically adjustable baille I4 is positioned in the offset i0 adjacent the downstream portion 9b of thespout 9. This barile I4 can be adjusted up and down upon its support I5 and held in adjusted position by bolts and nuts I6. The lower edge I1 of baffle il cooperates with the upper face I8 of the porous brickJS to form an opening 20 through which the cement passes. The upper edge 2| of bafiie I4 cooperates with the top wall 22 of the offset I0 to form an opening 23 through which the cement passes. Thus the size of opening 20 is increased by an upward adjustment of baffle I l vrluidify the same.

and decreased by a downward adjustment thereof. 'Ihe size of opening 23 is increased by a downward adjustment of baille I4 and decreased by an upward adjustment thereof. 'Ihis adjustment of the bailles I4 and vII is a factor in determining and controlling the rate of ow or'volume of cement passing through the feed' er I0.

The offset III in the spout 9 with its horizontal bottom should be of sufficient length that it acts as an obstruction which will stop the normal flow of the unaerated cement through spout 9. One or both of the bailles I I and I4 are preferably, but not necessarily, inserted in the oil'set III so that the length of the voilsel; can be materially shortened. When a baille such as II or I4 is used, then the length of the horizontal offset portion Ill Iis preferably insufficient t stop the flow of material in its normal state. Thus the use of one or both of the bailles I4 materially adds to the compactness and appreciably decreases the size of the feeder. Further, the bailles also give precise and accurate control of the flow of the powdered material so that the flow of said material is coterminous with the flow of compressed air through porous medium I9.

Since the offset 'I0 with its preferred bailles II and I4 acts as an obstruction which stops the normal flow of cement through spout 9, it is essential in the operation of the feeder that means must be provided for overcoming this obstruction and effecting a flow of cement through the feeder. VThis object is achieved by introducing compressed air into the material at the point or in the area of the obstruction at sufficiently low pressure so that the air will filter into the cement and fiuidify the cement or intermix with the cement so that the resultant mixture of cement has the characteristic of a iiuid particularly from the standpoint of flow. The point is that the friction between the particles or grains of cement in its normal state is suilicient to prevent, the flow of the cement through offset I0 and past bailles II and I4. The introduction of air into the cement reduces this friction between the cement particles sufliciently to induce iiow. The air may be introduced into the cement at offset III through any suitable porous medium such as porous brisk, closely woven fabric, a multiplicity of small air jets, a block of sponge rubber, or filter stone. Preferably, although not necessarily, the size of the pores or the outlets of the air jets should be sufficiently small so that when the compressed air is not flowing through lthe pores or jets, cement particles will not be able to enter the pores or jets and obstruct or plug the same. Preferably the pores or jets should be sufiiciently small so that the air will flow into the cement in a finely divided state so that it will readily mix with the cement and As herein shown the element I9 is a porous refractory insulating brick which is supported above the bottom wall 24 of the feeder by supports 25 to provide an air space 25 between the bottom face of the brick I9 and the wall 24 of the feeder. Compressed air is admitted into space-26 from any suitable source of compressed air by pipe line 21 and inlet 28.

The operation of this device is as follows: The cement or other powdered material upon passing through outlet 3 will reach the feeder III. Assuming that the valve 3U in the compressed air line 21 is open, upon reaching the porous brick I9, the finely divided air emitted from the brick n will intermlx and iiuidify the cement so that it portion 9b of spout 9.

assumes the characteristics of a fluid. As thus fluidifled the cement will flow as indicated by the arrows through opening 29 beneath baille II and through opening 23 over baille I4, thence into the spout `9b. The instant that valve.39 is closed, shutting oil the flow of compressed air through porous brick I9, the cement ceases to be aerated, loses its iiuid characteristics, and ceases to flow. 'I'hus the fiowof cement is practically coterminous` with the flow of compressed air through the porous insulating brick I9. In actual practice the pressure of the air in space 25 has been maintained approximately at i'lve pounds per square inch. However, pressures lower than this and as high as thirty pounds per square inch have been used satisfactorily. If pressures much higher than this are used, the air tends to pass through the cement in streams and aeration or fluidifying of the cement is impaired as the pressure increases.

In Fig. 3 a modified form ofthe feeder is shown which is practically the same as the principal form except that the need for the baffles II and I4 has been obviated by positioning the offset I9 inthe spout 9 so that it is inclined upwardly in the direction of`fiow of the iluldii'led cement indicated by the arrows. Thus the upper wall 22, the floor 24 and the porous brick I9, are all positioned at an angle to the horizontal and are upwardly inclined in the direction of flow of the cement. The angle or upward inclination of the offset I0 is suchthat the downward gravitational ow of the unaerated cement in its normal powdered condition is obstructed, and stopped. In other words, the friction between the particles of cement is such that in its normal unaerated state it cannot flow from the upstream portion 9a of the spout 9 through the upwardly inclined feeder III into the downstream However, when com pressed air, as above described, is admitted through pipe line 21 into space 26 from whence it flows through porous brick I9 and aerates or uidies the cement, then the cement assumes A the characteristic of a fluid and Vflows freely through the feeder III. Here again when the compressed air is turned off by closing valve 30. fiow of the cement ceases.

In Fig. 4 a second modified form of feeder is shown. In,this form of the invention the spout 59 is provided with a plurality of adjustable horizontal bailles 33 positioned alternately on opposite sides of the upright spout 59 so that the cement in passing by the baiiles will have to take the circuitous route indicated by the arrows. The arrangement of the bailles is such that the cement in its normal unaerated state cannot flow by the baffles, that is, the flow of the cement in its normal condition is arrested or completely stopped by the `bailles 33. To fluidity the cement a plurality of openings 34 are provided in the spout 59, preferably one opposite the inner end of each baille 33. A fine mesh or closely woven fabric 3S is secured over each opening 34 by means of housing 31 which is secured to the spout by bolts 39. A porous brick may be substituted for fabric 35. Compressed air passes from the feed line 21 through the fabric 36 in each opening 34 to aerate or fiuidify the cement. Thus the flow of cement through the spout 59 is controlled by the flow of compressed air through fabric 36, that is, as longas compressed air is flowing through line 21 and fabric 35, the cement is aerated and flows through the spout 59 and as soon as the compressed air is turned` oil and ceases to flow through fabric 36 the flow of cement ceases.

It should be noted that in the two forms of the invention shown in Figs. 1 and 3 that the porous medium I9 actually acts as a baille in the spout 9 for obstructing the ow of the cement in its normal condition. As used herein normal condition of the cement means the condition of the cement when it is not aerated or iluidilled by the compressed gas passing through the porous medium.

I claim:

1. In combination with a conduit through which powdered material flows from an inlet end to a lower outlet end, said conduit having a transverse portion with its bottom wall positioned horizontally, a baille in said transverse portion extending in a substantially vertical plane for stopping the flow of said material in its normal condition through the conduit, a porous medium positioned in the bottom of said transverse portion,

and means for forcing gas at low pressure through said porous medium to iiuidify the said material whereby' said material while thus iiuidiiled flows by vgravity through said conduit and transverse portion.

l2. In combination with a substantially vertical conduit through which a powdered material ilows with the aid of gravity. a horizontal conduit portion communicating with the vertical portion having a length of itself insutllcient to stop the flow of said material in its normal condition. a bailie for partially obstructing thehorizontal portion of said conduit, the said horizontal conduit portion cooperating with vthe baille to stop the flow of material in its normal condition through the conduit, a porous medium in said horizontal portion, and means for forcing gasl portion of said conduit, the said horizontal conduit portion cooperating with the baille to stop the ow of material in its normal condition through the conduit, a porous medium in said 5 horizontal portion, and means for forcing gas at low pressure through said porous medium to iluidify said powdered material whereby said material while thus fiuidified flows by gravity through said conduit and horizontal portion.

4. In combination with a substantially vertical conduit through which a powdered material flows with the aid of gravity, a horizontal conduit portion communicating with the vertical portion oi' size insuilicient to stop the ilow of said material i5 in its normal condition, a porous medium in said horizontal portion, a baille extending upwardly from the down-now end of the bottom wall of said horizontal conduit portion for partially obstructing the horizontal portion of said conduit, the said horizontal conduit portion cooperating with the .bame to stop the ilow of material in its normal condition through the conduit, and means for forcing gas at low pressure through said porous 'medium to fluidify said powdered material wherebysaid material while thus iluidied iiows by gravity through said conduit and horizontal portion 5. In combination with a substantially vertical conduit through which a nely divided material in its normal condition ows by gravity. a horizontal conduit portion communicating with the vertical portion of size insuilicient to stop the flow of said material in its normal condition, a baille extending upwardly from the bottom wall of said horizontal conduitportion for partially obstructing the horizontal portion of said confled hows by gravity through said cmdult and horizontal portion.

HENRY RIPLEY 

